A number of different types of security systems have been designed or proposed which include a central controller and a plurality of remote sensors designed to respond to a particular, possibly hazardous environmental condition, such as fire, an intruder, explosive or poisonous gas, temperature extremes, radiation, water, etc., or to several such conditions. The central controller monitors the status of the various sensors and sounds an alarm in response to a potentially hazardous condition detected by one or more of the sensors.
The great majority of such systems are designed to be permanently installed with the controller permanently wired to the various sensors and permanently wired into the AC electrical distribution system available at the location.
In some instances, systems have been proposed which include wireless radio links between the sensors and the central processing unit. However, in such systems, the central processing unit, the detectors or both remain hard wired into the AC power distribution system available at the location where the system is installed.
In addition, many of these systems are modular. The central processor may be provided with circuitry for responding to an alarm signal received from a remotely located sensor and, through the provision of separate components may respond to the condition in various ways, such as by activating an audible and/or visual alarm, automatically dialing a remote or central fire fighting or security installation, etc. In the known systems, these components are selectively provided, may be permanently mounted, and are typically hard wired into the controller, a power supply at the location, or both.
The loss of such existing systems, even on a temporary basis, can have significant impact. For example, in some localities, even the temporary loss of a hard wired fire detection system in a hospital requires the hospital to immediately evacuate all patients in areas monitored by the disabled detectors. In many working environments, the loss of sensors indicating the presence of radiation, hazardous or explosive gases or other toxic or dangerous material necessitate immediate shutdown and evacuation of the monitored areas. No known system is capable of being quickly and temporarily installed in such instances without some type of jerry-rigged, hard wire connections between sensors and their controller or any one of them and a power supply.